Dual battery charging set up and parallel battery winching

The current set up I have is the Crank battery and Aux battery and a Surge Power 1314 Battery Isolator to control the charging of the Aux battery.

The winch and caravan brake controller come of the Crank battery. Other items e.g. radio, sat phone fridge outlet come of the Aux battery.

What I want to do is link the Crank and Aux batteries in parallel when I winch. This is to cover the case where I can't sit in the cab and have my foot on the accelerator peddle, as my Patrol does not have a hand throttle.

The wiring is I suspect relative simple.

What I am not sure about is if I should use something like the Redarc Dual Sensing Smart Start SBI 12V 200A (SBI212D), or go for a 25A In-Vehicle Battery Charger/MPPT Regulator (BCDC1225).

I assume the battery charger system will charge both batteries better than using the SB1 unit.

I was told somewhere/some time ago that I had to isolate the Aux battery as I have a brake controller.
Does this mean I need both the SB1 and BCDC, or just the BCDC?

I realise that if I use a BCDC unit I have to disconnect its operation when winching in parallel.

Correct me if im wrong but the bcdc device will not link batteries ever.... it is basically a one way battery charger which runs off your start battery/alternator. The only way to link batteries for winching is with a redarc SBI212d or similar with jump start override capabilities or simply get a cole hersy heavy duty solenoid and use that as a link. As i already have a piranha dual batt system (no override) im looking at running a cole hersey manual solenoid for winching/jump starting.

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Yes the BCDC units are one way.
That is why I said I would have to have it disconnected, the BCDC unit, electrically if winching with parallel batteries.
Unless I am wrong this will require 2 heavy duty relays/solenoids, one on the Crank battery to BCDC unit wire and one on the Crank – Aux batteries +ve link wire.

Even with an SBI212D I will require some relays, but not much more than about 10 amps.

I suppose it basically comes down to what is the best way to charge both batteries, the SBI212D or a BCDC unit.

Where is your second batt located? Is it a cranking batt/hybrid or deep cycle? Unless it is many meters away from the alternator (or low volatage one) or your using undersized cables to the aux batt then a basic smart relay systems will work just as effective if not more than a bcdc unit. So why not simply use the SBI212d for the job? It is capable of 200A continuous and 600A surge? Why add more relays? I believe it has an inbuilt override you just need to add a switch.

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Considering you already have a dual batt system and assuming it does the job, i would be inclined to simply add a switch and 200A relay across the winch which bypasses the dual batt sys. I dont see any need to disconnect the existing setup using 2 solenoid. You can pick one up for easily under $150, under $100 if not genuine cole hersee.

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At present I have a lean toward the SBI unit approach. As it is the cable to the aux is not big enough as a return so it need replacing. Both batteries are in the engine bay and deep cycle.

Deep cycles aren't exactly orientated towards huge current draw. You do really need a high CCA battery to take advantage of anything like winching. I would also assume (i have no actual idea) that it may shorten the life of a deep cycle utilising it for cranking / winching.

If I was going to upgrade my dual batt system and wiring I would definitely be considering the redarc SBI212d.

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First up there was a recall on the power surge 1314 so hopefully your awear of that..
http://www.cooperindustries.com/cont...l_info_NA.html

Secondly the power surge seems to be similar to a voltage sensing solinode but only one way..

Imo for the $120 I'd replace the 1314 with the redarc voltage sensing solinode and add the overide switch. When winching switch it on. And let it do its own thing when not..
From memory the redarc is a 500 amp burst 200 amp constant solinode.
You'll also want a good size cable to between the batteries.. I have 30mm2 between mine.. good for 300 consistent load

The redarc for around $90 is only single sensing 100a w/ burst 400a. The dual sensing 100a is around $150. The 200a dual sensing w/ burst 600a is around $300 (autoelecau). I read somewhere yesterday that Redarc even state that the 100a isn't ideal for winching (i thought i even read it may void warranty but couldn't find it again)

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Checked the recall and mine is not in that batch.
The 1314 is one way so not useful for what I am looking at.

As far as batteries go these are getting close to end of life so new ones are a minor issue, also on the list.

I have had a talk with REDARC and they say the SBI 212D for this. You need to consider a working load around 200 amps.

Wen talking o them I just forgot to discuss the matter of the BCDC unit as well.